Magnetic rotary position sensor designed for automotive safety

By Warren Miller, contributing writer

Magnetic sensors are implemented in all kinds of mechanical and electronic mechanisms, including automobiles. When implemented in the steering system, they can detect if and when a vehicle is in danger of spinning out of control. Ams recently announced the release of the AS5200L, a dual-die magnetic rotary position sensor with an I² C interface that’s well suited for the development of systems critical to automotive safety. The device is AEC-Q100 Grade 1-qualified.

The AS52001 is the latest addition to the ams line of magnetic position sensors designed for electrified powertrain drive-by-wire functions employed in both manual and automatic transmission vehicles. The dual dies each include separate package pins to prevent an electrical fault in the system from adversely affecting both measurement outputs.

The AS52001 is contained within an MLF-16 package and measures 5 x 5 mm, potentially saving valuable space in smaller development environments like gear shifts, pedals, or other contactless potentiometer applications. Its I² C interface allows it to be easily programmed by a host microcontroller, eliminating the need for a dedicated programmer. The AS52001 also operates on low power in both active and standby modes.

The use of dual dies is a plus in systems in which redundancy and reliability are important, such as in automotive applications. The robust design of the device eliminates susceptibility to stray external magnetic fields. This improves reliability and accuracy of position measurements. A diagnostic feature also improves safety and reliability by reporting the absence of a magnet. If the magnetic field strength goes below a minimum, it is captured in a status register and can also be indicated on the output pin.

The AS5200L offers low power consumption in active and standby modes. A smart low-power mode further improves energy efficiency and automatically enters the lowest-power mode if the angle doesn’t change for at least a minute. The normal supply current can be reduced from the 6.4-mA range, when the device is always on, to 1.5 mA with a 100-ms polling time. Intermediate settings are also possible, allowing the application to select an optimal polling time and operational current combination.

An evaluation board for the AS5200L is available from the ams ICdirect online store. For sample requests or for more technical information, go to www.ams.com/Position-Sensors/ AS5200L.